1. Technical Field
The field of the currently claimed embodiments of this invention relates to medical devices, and more particularly to anchoring medical devices within a tissue cavity.
2. Discussion of Related Art
The need for temporary protection of the bowel lumen from fecal flow after surgical bowel resection and anastomosis or when the bowel wall is damaged has traditionally been accomplished by the creation of an external diversion of the bowel through the creation of an ostomy. An ostomy is a purposeful anastomosis between a segment of the gastrointestinal (GI) tract and the skin of the anterior abdominal wall. An ostomy can be created virtually anywhere along the GI tract. For diversion of the fecal stream, the most common ostomies involve the distal small intestine (e.g., ileostomy) and large intestine (e.g., colostomy). Ostomies are performed in 300,000 patients in the US and over 2 million patients globally, but this surgery is complicated by high morbidity, mortality, and severe impact on a patient's quality of life. Although many ostomies are intended to be temporary, as many as ⅓ of temporary ostomies are never reversed. Accordingly, there is a need for improved method and devices to provide a less morbid alternative for fecal diversion.
One of the major indications for a temporary ostomy is to protect a bowel anastomosis from enteric contents that can lead to anastomotic leaks. An anastamotic leak is defined as a defect of the intestinal wall at the anastomotic site leading to a communication between the intra- and extraluminal compartments. Anastamotic leaks after bowel surgery is a major complication. The overall incidence of colorectal anastomotic leak varies widely in the literature, ranging from 1 to 24%. Leaks can cause severe complications such as loss of the anastomosis, sepsis, and death. Even in those cases where the anastomosis is salvaged, poor compliance in the neorectum can lead to a poor functional outcome. In many large studies, anastamotic leaks has been shown to be associated with a pelvic sepsis at a rate of 50%. By protecting the anastomosis from fecal flow, anastamotic leaks may be prevented or their morbidity mitigated. In addition, even after an anastamotic leak has occurred, protection from fecal flow can make the anastamotic leak less severe and aid in healing of the leak. There are several risk factors for the development of an anastamotic leak. The most significant risk factor is the level of the anastomosis, with the leak rate increasing as the distance from the anastomosis to the anus decreases. Other than meticulous technique in creating the anastomosis, the major strategy to prevent and treat anastamotic leaks during complicated or high-risk cases involving bowel resection is to divert fecal flow. This is accomplished by having the flow of gastric contents diverted using an ostomy created in the bowel proximal to the anastomosis. Proximal in the bowel is defined as higher up in the GI tract towards the mouth, distal in the bowel is defined as lower down in the GI tract towards the anus. This ostomy can be either an end ostomy such as an end colostomy or end ileostomy or can be a diverting loop ileostomy that does not completely disrupt bowel continuity.
A temporary diverting ostomy and its closure has its own set of complications and morbidities including dehydration due to high output, difficulty with ostomy care, stricture at the closure site, wound infections, and incisional hernias. Complication rates of ostomies range between 5% and 100%. The complications can be divided into minor complications, which do not require surgical intervention, and major complications requiring surgical intervention. Major complications include stenosis, small bowel obstruction, retraction, necrosis, prolapse, stricture, fistula, and parastomal hernia. In some cases, such as partial small bowel obstruction, the patient can first be treated conservatively and surgical intervention may be avoided. Major complications such as ostomy necrosis that extends more than a few millimeters, surgical intervention is mandatory. Minor complications include dermatitis, electrolyte imbalance, and dehydration from high ostomy output, although the last often necessitates early closure of the ostomy. For major complications, additional costs and morbidity associated with additional operations or hospitalizations can be significant. Even for minor complications, treating complications and providing ostomy education can be burdensome to healthcare providers and patients. Some complications such as hernia, prolapse, and stenosis may become chronic and often require multiple corrective operations and associated costs. Ostomies also significantly reduce a patient's quality of life. Fecal output from the ostomy is collected into an ostomy bag attached to the patient's abdomen. These bags need to be emptied and replaced regularly to properly care for the ostomy and prevent unintentional discharge of fecal material.
Furthermore, the reversal of an ostomy is a surgical procedure fraught with potential complications, as often times the abdominal compartment has dense adhesions that make re-establishment of normal bowel continuity both costly and potentially morbid. In addition to expenses associated with taking patients to the operating room, patients typically require a hospitalization of 2-4 days post-procedure to allow for support until bowel function returns. Furthermore, the reversal of an ostomy may be difficult or impossible in some patients, requiring the patient to live the rest of their life with an ostomy. The repaired bowel after ostomy takedown may also develop a leak at the repair site or anastomotic site in cases of loop ileostomies or in cases of end ostomy reattachment, respectively.
Besides anastomotic protection, there are other potential indications for temporary fecal diversion. These include: 1) treatment of an anastomotic leak after it has occurred, 2) diverticulitis, 3) inflammatory bowel diseases such as Crohn's or Ulcerative Colitis, 4) intestinal perforation and 5) other less common instances of bowel injury where fecal diversion could be useful such as in cases of ischemic bowel disease, bowel contusion injury from trauma, or non-healing perineal/perianal wounds. When a leak or bowel perforation has occurred such as in cases of anastomotic leak and diverticulitis as examples, treatment with fecal diversion can reduce the severity and extent of the condition. Thus, these patient may heal their leak/perforation faster and not develop more severe complications when continued fecal flow contamination of the affected site is mitigated. Inflammatory conditions of the bowel wall such as Crohn's disease or Ulcerative Colitis can make the intestinal lining susceptible to damage from fecal flow. Continued fecal flow can further inflame and contaminate the bowel wall and lead to worsening of patient's overall disease or even frank perforation of the bowel wall. Protection from fecal flow allows the inflamed sections of bowel to rest and heal, and potentially fecal diversion could reduce recovery time, hospitalization time, and limit severe complications such as perforations or fistula formation. Patients with these conditions may not be good candidates for surgery due to their concomitant conditions or sepsis; thus, performing major surgery to create an ostomy can be morbid in these cases. Accordingly, there is a need for improved method and devices to provide a less morbid alternative for fecal diversion.
In the past, the concept of an intraluminal sheath for internal fecal diversion has been described (U.S. Pat. No. 4,716,900; U.S. Pat. No. 4,905,693; U.S. Patent Application Publication No. 2010/0010519). The principal challenge has been developing a device that can anchor securely within the bowel without harming the bowel wall itself and effectively accomplishing air and fluid tight fecal flow diversion. Staple and suture based techniques for devices such as those described by Ravo et al. (U.S. Pat. No. 4,716,900), Ravo (U.S. Pat. No. 4,905,693), and Stopek et al. (U.S. Patent Application Publication No. 2010/0010519) are both potentially harmful to the area of bowel damage from traction and cannot achieve effective sheath anchoring without major surgery. Other methods of anchoring within the bowel have also been described that dependent on scar formation to secure an anchor in place such as the device described by Baker (U.S. Patent Application Publication No. 2008/0215076). This method however is not easily reversible and depends on the body's scar forming ability which may be compromised in some patients for secure anchoring. There have also been stent-based anchors such as the devices described by Khosrovaninejad (U.S. Patent Application Publication No. 2011/0295288), Levine et al. (U.S. Pat. No. 7,267,694), Rockey (U.S. Pat. No. 4,641,653) and Bessler et al. (U.S. Pat. No. 7,211,114), but stents do not provide enough anchor strength to hold the sheath firmly in place during bowel peristalsis as evidenced by their high rate of premature expulsion, and may further damage the bowel wall due to the necessary rigidity and expansion force they exert to provide anchoring. Others have attempted using a fixed biodegradable ring anchor placed outside and around the bowel wall such as Assaf et al. (U.S. Patent Application Publication No. 2013/0158463), but this approaches also requires major surgery for placement and exposes the bowel to potential erosion and damage due to pressure points exerted on the bowel wall. In addition, the necessity of creating a substantial air and fluid tight bypass of fecal contents has also been a technical challenge. Inflatable balloon types of seals such as those described by Assaf et al. (U.S. Patent Application Publication No. 2013/0158463) and Weig (U.S. Pat. No. 8,388,586 and U.S. Patent Application Publication No. 2010/0022976) have been described to try and achieve air and fluid tight seals within the intestines, but these again require potentially harmful expansible forces and pressure on the bowel wall to form a seal and often fail to achieve an adequate air and fluid tight barrier to enteric flow.
Negative pressure wound therapy has been used to treat anastomotic leaks in the past, and these dressings typically utilize a foam interface over the damaged area of bowel covered by an occlusive barrier connected to a negative pressure source. Devices specifically designed to treat wounds and provide negative pressure treatment in the intestine or body cavities have been described (U.S. Patent Application Publication No. 2013/0190706, U.S. Pat. No. 8,926,576, and U.S. Patent Application Publication No. 2015/0250979). Importantly, these devices are designed to be placed and to deliver negative pressure at the site of an anastomosis or tissue damage and as a result can cause further damage to the area of the anastomosis or tissue damage when longitudinal forces are placed on these devices or negative pressure ischemia is induced. These devices are not designed to protect the bowel lumen distal to the site of placement. These types of dressing devices for negative pressure wound therapy have difficulty establishing and maintaining air tight seals and become frequently dislodged due to their lack of adequate sealing mechanisms. Furthermore, these devices are not configured in a way to withstand the additional longitudinal forces that can displace the device with the addition of a protective sheath. Lastly, these devices employ expandable wire-stent based designs to provide semi-rigid structure (U.S. Patent Application Publication No. 2013/0190706, U.S. Pat. No. 8,926,576, and U.S. Patent Application Publication No. 2015/0250979) that can create tissue damage and make them more prone to expulsion from the bowel due to peristaltic forces. Khosrovaninejad (U.S. Patent Application Publication No. 2014/0222039) has used negative pressure suction to attempt to anchor a protective sleeve within the bowel. The major issues with this device are that the attachment and anchoring of the device is dependent on the adherence forces of negative pressure delivered via perforations and the radial expansion force of a stent-based design. Perforations do not allow for adequate friction force to be generated to substantially fix a device in place and resist the expulsion forces of the bowl. Thus, this device is designed to be expulsed from the body after several days and must be placed very high above an area to be treated. Furthermore, the expansile stent-based design suffers from the same issues of other stent-based designs of potential bowel damage and expulsion. Accordingly, there needs to be a device and method that can securely anchor within a body cavity in a controlled fashion that has an improved safety profile and increased anchoring strength and reliability.